Computing-machine



(No Model.)

R. E. MOGLBLLAND. COMPUTING MACHINE.

No. 532,241 Patented Jan. 8, 1895.

Wifnesscs Invcni-01-z- UNITED STATEs PATENT OFFICE ROBERT E. MOCLELLAND, OF WILLIAMSVILLE, ILLINOIS.

COMPUTING-MACHINE.

SPECIFICATION forming part of Letters Patent No. 532,241, dated January 8, 1895.

Application filed April 11, 1894. Serial No. 507,118. (No model.)

T (0% whom it 11mg concern.-

Be it known that I, ROBERT E. MUOLEL- LAND, a citizen of the United States, residing at l/Villiamsville, in the county of Sangamon and State of Illinois, have invented a new and useful Improvement in Computing-Machines, of which the following is a specification.

My invention is an adding ruler the object of which is to assist by mechanical means the mental operation of adding a series of figures together to find their sum. This I do with theinstrument shown in the drawings in which Figure 1 is a general top view of the in strument at small scale. Fig. 2 is a longitudinal section. Fig. 8 is a cross section through the center of the ruler. Fig. 4- is a cross section through the pulley F, and Fig. 5 is a top View of one end showing letters and marks not clearly shown in Fig. 1.

Similar letters refer to throughout the several figures.

The adding ruler consists of a wood ruler A of ordinary size and shape such as is commonly used by book-keepers and accountants. The adding device is inserted in this ruler A and is composed of first, two flat thin pieces of metal a and b of length the same as the wood ruler A and inserted in grooves in the wood so as to be flush with the surface. One plate I) is placed on the under side and is plain. The other plate a is set on the top side of the ruler and has a narrow slot 0 cut in the center for a greater part of its length, the slot 0 not extending to either end, how ever, as shown in Fig. 1. On a, at one side of the slot 0, is a scale a: marked in numbers from 1 to 40. There is a rectangular hole (Z in or near its right end, and a circular hole, grooved in its perimeter, in which a circular index wheel to is placed and which revolves in the said groove. A metal belt ribbon 0,

similar parts numbered in equal parts from 1 to 100, is placed to run beneath the plates a and b and at the points near the ends of the ruler pass around the pulleys F and G so that G can be easily rolled in its position in the ruler.

The ribbon G has small holes 0 c c between the numbers on G into which a pencil point, or other pointed instrument may be inserted, and C be moved thereby. As O is moved the figures on C pass under the rectangular hole (1 which is the reading point of the ruler, a single number always stopping at (Z.

The pulleys F and G are placed in A near the ends and are secured on pinions so that they may easily turn. They are of the width of the ribbon O which passes around them. On the ribbon 0 near its edge is a small nib e which has a slight projection above the surface of O. The object of the nib e is to move the index wheel to when e passes under to so that 100 may be registered by w. The nib e is located on O at such a distance from the hundred number that, as the hundred number passes beyond the opening (Z, c will move the index wheel 20 part way round and thus indicate that one hundred has been enumerated. The index wheel 10 revolves in its position in a and has on its face several figures from 1 to 5 or more, each indicating a number of hundreds. The under side of w is made with as many lugs as hundreds are indicated on against which the nib strikes in its movement thus turning 20 part round.

To use the instrument it is laid on the desk or held in the hand. Before commencing it is made ready by setting the ribbon O to read 100 under the opening (Z which is the same as zero in beginning an addition. The index wheel to is set at 0 also, indicating no hundreds. In running up the column of figures to be added the point of a pencil is placed consecutively in the holes 0 c c in the ribbon O at the number on the scale 00 corresponding with the number to be added, and push to the right till the end of the slot 0 is reached. After the figures are followed through consecutively in this way their sum may be found by reading the number on the ribbon 0 showing through the hole (Z. If the sum exceeds the number 100 the hundreds will be read on the index wheel to.

The process may be Varied by the operator adding several of the numbers mentally and hen C with holes 0 0 c and nib e, pulleys F thenmovingUfrom thepoint expressing their and G all substantially as and for the purto sum. poses set forth.

Having thus described my invention What v y 5 I desire to secure by Letters Patent is- Rob MCOLELLAND' An adding ruler composed of the Wood ruler Vitnesses: A, "the plate a, with slot 0, hole cl, index wheel \V. L. PEROE,

w and scale m, the plate Z), the movable rib- J. P. TURLEY. 

